fs/cifs/readdir.c

   1 // SPDX-License-Identifier: LGPL-2.1
   2 /*
   3  *
   4  *   Directory search handling
   5  *
   6  *   Copyright (C) International Business Machines  Corp., 2004, 2008
   7  *   Copyright (C) Red Hat, Inc., 2011
   8  *   Author(s): Steve French (sfrench@us.ibm.com)
   9  *
  10  */
  11 #include <linux/fs.h>
  12 #include <linux/pagemap.h>
  13 #include <linux/slab.h>
  14 #include <linux/stat.h>
  15 #include "cifspdu.h"
  16 #include "cifsglob.h"
  17 #include "cifsproto.h"
  18 #include "cifs_unicode.h"
  19 #include "cifs_debug.h"
  20 #include "cifs_fs_sb.h"
  21 #include "cifsfs.h"
  22 #include "smb2proto.h"
  23 #include "fs_context.h"
  24 #include "cached_dir.h"
  25
  26 /*
  27  * To be safe - for UCS to UTF-8 with strings loaded with the rare long
  28  * characters alloc more to account for such multibyte target UTF-8
  29  * characters.
  30  */
  31 #define UNICODE_NAME_MAX ((4 * NAME_MAX) + 2)
  32
  33 #ifdef CONFIG_CIFS_DEBUG2
  34 static void dump_cifs_file_struct(struct file *file, char *label)
  35 {
  36         struct cifsFileInfo *cf;
  37
  38         if (file) {
  39                 cf = file->private_data;
  40                 if (cf == NULL) {
  41                         cifs_dbg(FYI, "empty cifs private file data\n");
  42                         return;
  43                 }
  44                 if (cf->invalidHandle)
  45                         cifs_dbg(FYI, "Invalid handle\n");
  46                 if (cf->srch_inf.endOfSearch)
  47                         cifs_dbg(FYI, "end of search\n");
  48                 if (cf->srch_inf.emptyDir)
  49                         cifs_dbg(FYI, "empty dir\n");
  50         }
  51 }
  52 #else
  53 static inline void dump_cifs_file_struct(struct file *file, char *label)
  54 {
  55 }
  56 #endif /* DEBUG2 */
  57
  58 /*
  59  * Attempt to preload the dcache with the results from the FIND_FIRST/NEXT
  60  *
  61  * Find the dentry that matches "name". If there isn't one, create one. If it's
  62  * a negative dentry or the uniqueid or filetype(mode) changed,
  63  * then drop it and recreate it.
  64  */
  65 static void
  66 cifs_prime_dcache(struct dentry *parent, struct qstr *name,
  67                     struct cifs_fattr *fattr)
  68 {
  69         struct dentry *dentry, *alias;
  70         struct inode *inode;
  71         struct super_block *sb = parent->d_sb;
  72         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
  73         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
  74
  75         cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
  76
  77         dentry = d_hash_and_lookup(parent, name);
  78         if (!dentry) {
  79                 /*
  80                  * If we know that the inode will need to be revalidated
  81                  * immediately, then don't create a new dentry for it.
  82                  * We'll end up doing an on the wire call either way and
  83                  * this spares us an invalidation.
  84                  */
  85                 if (fattr->cf_flags & CIFS_FATTR_NEED_REVAL)
  86                         return;
  87 retry:
  88                 dentry = d_alloc_parallel(parent, name, &wq);
  89         }
  90         if (IS_ERR(dentry))
  91                 return;
  92         if (!d_in_lookup(dentry)) {
  93                 inode = d_inode(dentry);
  94                 if (inode) {
  95                         if (d_mountpoint(dentry)) {
  96                                 dput(dentry);
  97                                 return;
  98                         }
  99                         /*
 100                          * If we're generating inode numbers, then we don't
 101                          * want to clobber the existing one with the one that
 102                          * the readdir code created.
 103                          */
 104                         if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM))
 105                                 fattr->cf_uniqueid = CIFS_I(inode)->uniqueid;
 106
 107                         /* update inode in place
 108                          * if both i_ino and i_mode didn't change */
 109                         if (CIFS_I(inode)->uniqueid == fattr->cf_uniqueid &&
 110                             cifs_fattr_to_inode(inode, fattr) == 0) {
 111                                 dput(dentry);
 112                                 return;
 113                         }
 114                 }
 115                 d_invalidate(dentry);
 116                 dput(dentry);
 117                 goto retry;
 118         } else {
 119                 inode = cifs_iget(sb, fattr);
 120                 if (!inode)
 121                         inode = ERR_PTR(-ENOMEM);
 122                 alias = d_splice_alias(inode, dentry);
 123                 d_lookup_done(dentry);
 124                 if (alias && !IS_ERR(alias))
 125                         dput(alias);
 126         }
 127         dput(dentry);
 128 }
 129
 130 static bool reparse_file_needs_reval(const struct cifs_fattr *fattr)
 131 {
 132         if (!(fattr->cf_cifsattrs & ATTR_REPARSE))
 133                 return false;
 134         /*
 135          * The DFS tags should be only intepreted by server side as per
 136          * MS-FSCC 2.1.2.1, but let's include them anyway.
 137          *
 138          * Besides, if cf_cifstag is unset (0), then we still need it to be
 139          * revalidated to know exactly what reparse point it is.
 140          */
 141         switch (fattr->cf_cifstag) {
 142         case IO_REPARSE_TAG_DFS:
 143         case IO_REPARSE_TAG_DFSR:
 144         case IO_REPARSE_TAG_SYMLINK:
 145         case IO_REPARSE_TAG_NFS:
 146         case 0:
 147                 return true;
 148         }
 149         return false;
 150 }
 151
 152 static void
 153 cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
 154 {
 155         fattr->cf_uid = cifs_sb->ctx->linux_uid;
 156         fattr->cf_gid = cifs_sb->ctx->linux_gid;
 157
 158         /*
 159          * The IO_REPARSE_TAG_LX_ tags originally were used by WSL but they
 160          * are preferred by the Linux client in some cases since, unlike
 161          * the NFS reparse tag (or EAs), they don't require an extra query
 162          * to determine which type of special file they represent.
 163          * TODO: go through all documented  reparse tags to see if we can
 164          * reasonably map some of them to directories vs. files vs. symlinks
 165          */
 166         if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
 167                 fattr->cf_mode = S_IFDIR | cifs_sb->ctx->dir_mode;
 168                 fattr->cf_dtype = DT_DIR;
 169         } else if (fattr->cf_cifstag == IO_REPARSE_TAG_LX_SYMLINK) {
 170                 fattr->cf_mode |= S_IFLNK | cifs_sb->ctx->file_mode;
 171                 fattr->cf_dtype = DT_LNK;
 172         } else if (fattr->cf_cifstag == IO_REPARSE_TAG_LX_FIFO) {
 173                 fattr->cf_mode |= S_IFIFO | cifs_sb->ctx->file_mode;
 174                 fattr->cf_dtype = DT_FIFO;
 175         } else if (fattr->cf_cifstag == IO_REPARSE_TAG_AF_UNIX) {
 176                 fattr->cf_mode |= S_IFSOCK | cifs_sb->ctx->file_mode;
 177                 fattr->cf_dtype = DT_SOCK;
 178         } else if (fattr->cf_cifstag == IO_REPARSE_TAG_LX_CHR) {
 179                 fattr->cf_mode |= S_IFCHR | cifs_sb->ctx->file_mode;
 180                 fattr->cf_dtype = DT_CHR;
 181         } else if (fattr->cf_cifstag == IO_REPARSE_TAG_LX_BLK) {
 182                 fattr->cf_mode |= S_IFBLK | cifs_sb->ctx->file_mode;
 183                 fattr->cf_dtype = DT_BLK;
 184         } else { /* TODO: should we mark some other reparse points (like DFSR) as directories? */
 185                 fattr->cf_mode = S_IFREG | cifs_sb->ctx->file_mode;
 186                 fattr->cf_dtype = DT_REG;
 187         }
 188
 189         /*
 190          * We need to revalidate it further to make a decision about whether it
 191          * is a symbolic link, DFS referral or a reparse point with a direct
 192          * access like junctions, deduplicated files, NFS symlinks.
 193          */
 194         if (reparse_file_needs_reval(fattr))
 195                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 196
 197         /* non-unix readdir doesn't provide nlink */
 198         fattr->cf_flags |= CIFS_FATTR_UNKNOWN_NLINK;
 199
 200         if (fattr->cf_cifsattrs & ATTR_READONLY)
 201                 fattr->cf_mode &= ~S_IWUGO;
 202
 203         /*
 204          * We of course don't get ACL info in FIND_FIRST/NEXT results, so
 205          * mark it for revalidation so that "ls -l" will look right. It might
 206          * be super-slow, but if we don't do this then the ownership of files
 207          * may look wrong since the inodes may not have timed out by the time
 208          * "ls" does a stat() call on them.
 209          */
 210         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL) ||
 211             (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MODE_FROM_SID))
 212                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 213
 214         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
 215             fattr->cf_cifsattrs & ATTR_SYSTEM) {
 216                 if (fattr->cf_eof == 0)  {
 217                         fattr->cf_mode &= ~S_IFMT;
 218                         fattr->cf_mode |= S_IFIFO;
 219                         fattr->cf_dtype = DT_FIFO;
 220                 } else {
 221                         /*
 222                          * trying to get the type and mode via SFU can be slow,
 223                          * so just call those regular files for now, and mark
 224                          * for reval
 225                          */
 226                         fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 227                 }
 228         }
 229 }
 230
 231 /* Fill a cifs_fattr struct with info from SMB_FIND_FILE_POSIX_INFO. */
 232 static void
 233 cifs_posix_to_fattr(struct cifs_fattr *fattr, struct smb2_posix_info *info,
 234                     struct cifs_sb_info *cifs_sb)
 235 {
 236         struct smb2_posix_info_parsed parsed;
 237
 238         posix_info_parse(info, NULL, &parsed);
 239
 240         memset(fattr, 0, sizeof(*fattr));
 241         fattr->cf_uniqueid = le64_to_cpu(info->Inode);
 242         fattr->cf_bytes = le64_to_cpu(info->AllocationSize);
 243         fattr->cf_eof = le64_to_cpu(info->EndOfFile);
 244
 245         fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
 246         fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
 247         fattr->cf_ctime = cifs_NTtimeToUnix(info->CreationTime);
 248
 249         fattr->cf_nlink = le32_to_cpu(info->HardLinks);
 250         fattr->cf_cifsattrs = le32_to_cpu(info->DosAttributes);
 251
 252         /*
 253          * Since we set the inode type below we need to mask off
 254          * to avoid strange results if bits set above.
 255          * XXX: why not make server&client use the type bits?
 256          */
 257         fattr->cf_mode = le32_to_cpu(info->Mode) & ~S_IFMT;
 258
 259         cifs_dbg(FYI, "posix fattr: dev %d, reparse %d, mode %o\n",
 260                  le32_to_cpu(info->DeviceId),
 261                  le32_to_cpu(info->ReparseTag),
 262                  le32_to_cpu(info->Mode));
 263
 264         if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
 265                 fattr->cf_mode |= S_IFDIR;
 266                 fattr->cf_dtype = DT_DIR;
 267         } else {
 268                 /*
 269                  * mark anything that is not a dir as regular
 270                  * file. special files should have the REPARSE
 271                  * attribute and will be marked as needing revaluation
 272                  */
 273                 fattr->cf_mode |= S_IFREG;
 274                 fattr->cf_dtype = DT_REG;
 275         }
 276
 277         if (reparse_file_needs_reval(fattr))
 278                 fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
 279
 280         sid_to_id(cifs_sb, &parsed.owner, fattr, SIDOWNER);
 281         sid_to_id(cifs_sb, &parsed.group, fattr, SIDGROUP);
 282 }
 283
 284 static void __dir_info_to_fattr(struct cifs_fattr *fattr, const void *info)
 285 {
 286         const FILE_DIRECTORY_INFO *fi = info;
 287
 288         memset(fattr, 0, sizeof(*fattr));
 289         fattr->cf_cifsattrs = le32_to_cpu(fi->ExtFileAttributes);
 290         fattr->cf_eof = le64_to_cpu(fi->EndOfFile);
 291         fattr->cf_bytes = le64_to_cpu(fi->AllocationSize);
 292         fattr->cf_createtime = le64_to_cpu(fi->CreationTime);
 293         fattr->cf_atime = cifs_NTtimeToUnix(fi->LastAccessTime);
 294         fattr->cf_ctime = cifs_NTtimeToUnix(fi->ChangeTime);
 295         fattr->cf_mtime = cifs_NTtimeToUnix(fi->LastWriteTime);
 296 }
 297
 298 void
 299 cifs_dir_info_to_fattr(struct cifs_fattr *fattr, FILE_DIRECTORY_INFO *info,
 300                        struct cifs_sb_info *cifs_sb)
 301 {
 302         __dir_info_to_fattr(fattr, info);
 303         cifs_fill_common_info(fattr, cifs_sb);
 304 }
 305
 306 static void cifs_fulldir_info_to_fattr(struct cifs_fattr *fattr,
 307                                        SEARCH_ID_FULL_DIR_INFO *info,
 308                                        struct cifs_sb_info *cifs_sb)
 309 {
 310         __dir_info_to_fattr(fattr, info);
 311
 312         /* See MS-FSCC 2.4.19 FileIdFullDirectoryInformation */
 313         if (fattr->cf_cifsattrs & ATTR_REPARSE)
 314                 fattr->cf_cifstag = le32_to_cpu(info->EaSize);
 315         cifs_fill_common_info(fattr, cifs_sb);
 316 }
 317
 318 static void
 319 cifs_std_info_to_fattr(struct cifs_fattr *fattr, FIND_FILE_STANDARD_INFO *info,
 320                        struct cifs_sb_info *cifs_sb)
 321 {
 322         int offset = cifs_sb_master_tcon(cifs_sb)->ses->server->timeAdj;
 323
 324         memset(fattr, 0, sizeof(*fattr));
 325         fattr->cf_atime = cnvrtDosUnixTm(info->LastAccessDate,
 326                                             info->LastAccessTime, offset);
 327         fattr->cf_ctime = cnvrtDosUnixTm(info->LastWriteDate,
 328                                             info->LastWriteTime, offset);
 329         fattr->cf_mtime = cnvrtDosUnixTm(info->LastWriteDate,
 330                                             info->LastWriteTime, offset);
 331
 332         fattr->cf_cifsattrs = le16_to_cpu(info->Attributes);
 333         fattr->cf_bytes = le32_to_cpu(info->AllocationSize);
 334         fattr->cf_eof = le32_to_cpu(info->DataSize);
 335
 336         cifs_fill_common_info(fattr, cifs_sb);
 337 }
 338
 339 /* BB eventually need to add the following helper function to
 340       resolve NT_STATUS_STOPPED_ON_SYMLINK return code when
 341       we try to do FindFirst on (NTFS) directory symlinks */
 342 /*
 343 int get_symlink_reparse_path(char *full_path, struct cifs_sb_info *cifs_sb,
 344                              unsigned int xid)
 345 {
 346         __u16 fid;
 347         int len;
 348         int oplock = 0;
 349         int rc;
 350         struct cifs_tcon *ptcon = cifs_sb_tcon(cifs_sb);
 351         char *tmpbuffer;
 352
 353         rc = CIFSSMBOpen(xid, ptcon, full_path, FILE_OPEN, GENERIC_READ,
 354                         OPEN_REPARSE_POINT, &fid, &oplock, NULL,
 355                         cifs_sb->local_nls,
 356                         cifs_remap(cifs_sb);
 357         if (!rc) {
 358                 tmpbuffer = kmalloc(maxpath);
 359                 rc = CIFSSMBQueryReparseLinkInfo(xid, ptcon, full_path,
 360                                 tmpbuffer,
 361                                 maxpath -1,
 362                                 fid,
 363                                 cifs_sb->local_nls);
 364                 if (CIFSSMBClose(xid, ptcon, fid)) {
 365                         cifs_dbg(FYI, "Error closing temporary reparsepoint open\n");
 366                 }
 367         }
 368 }
 369  */
 370
 371 static int
 372 _initiate_cifs_search(const unsigned int xid, struct file *file,
 373                      const char *full_path)
 374 {
 375         __u16 search_flags;
 376         int rc = 0;
 377         struct cifsFileInfo *cifsFile;
 378         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
 379         struct tcon_link *tlink = NULL;
 380         struct cifs_tcon *tcon;
 381         struct TCP_Server_Info *server;
 382
 383         if (file->private_data == NULL) {
 384                 tlink = cifs_sb_tlink(cifs_sb);
 385                 if (IS_ERR(tlink))
 386                         return PTR_ERR(tlink);
 387
 388                 cifsFile = kzalloc(sizeof(struct cifsFileInfo), GFP_KERNEL);
 389                 if (cifsFile == NULL) {
 390                         rc = -ENOMEM;
 391                         goto error_exit;
 392                 }
 393                 spin_lock_init(&cifsFile->file_info_lock);
 394                 file->private_data = cifsFile;
 395                 cifsFile->tlink = cifs_get_tlink(tlink);
 396                 tcon = tlink_tcon(tlink);
 397         } else {
 398                 cifsFile = file->private_data;
 399                 tcon = tlink_tcon(cifsFile->tlink);
 400         }
 401
 402         server = tcon->ses->server;
 403
 404         if (!server->ops->query_dir_first) {
 405                 rc = -ENOSYS;
 406                 goto error_exit;
 407         }
 408
 409         cifsFile->invalidHandle = true;
 410         cifsFile->srch_inf.endOfSearch = false;
 411
 412         cifs_dbg(FYI, "Full path: %s start at: %lld\n", full_path, file->f_pos);
 413
 414 ffirst_retry:
 415         /* test for Unix extensions */
 416         /* but now check for them on the share/mount not on the SMB session */
 417         /* if (cap_unix(tcon->ses) { */
 418         if (tcon->unix_ext)
 419                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_UNIX;
 420         else if (tcon->posix_extensions)
 421                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_POSIX_INFO;
 422         else if ((tcon->ses->capabilities &
 423                   tcon->ses->server->vals->cap_nt_find) == 0) {
 424                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_INFO_STANDARD;
 425         } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 426                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_ID_FULL_DIR_INFO;
 427         } else /* not srvinos - BB fixme add check for backlevel? */ {
 428                 cifsFile->srch_inf.info_level = SMB_FIND_FILE_DIRECTORY_INFO;
 429         }
 430
 431         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 432         if (backup_cred(cifs_sb))
 433                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 434
 435         rc = server->ops->query_dir_first(xid, tcon, full_path, cifs_sb,
 436                                           &cifsFile->fid, search_flags,
 437                                           &cifsFile->srch_inf);
 438
 439         if (rc == 0)
 440                 cifsFile->invalidHandle = false;
 441         /* BB add following call to handle readdir on new NTFS symlink errors
 442         else if STATUS_STOPPED_ON_SYMLINK
 443                 call get_symlink_reparse_path and retry with new path */
 444         else if ((rc == -EOPNOTSUPP) &&
 445                 (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 446                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 447                 goto ffirst_retry;
 448         }
 449 error_exit:
 450         cifs_put_tlink(tlink);
 451         return rc;
 452 }
 453
 454 static int
 455 initiate_cifs_search(const unsigned int xid, struct file *file,
 456                      const char *full_path)
 457 {
 458         int rc, retry_count = 0;
 459
 460         do {
 461                 rc = _initiate_cifs_search(xid, file, full_path);
 462                 /*
 463                  * If we don't have enough credits to start reading the
 464                  * directory just try again after short wait.
 465                  */
 466                 if (rc != -EDEADLK)
 467                         break;
 468
 469                 usleep_range(512, 2048);
 470         } while (retry_count++ < 5);
 471
 472         return rc;
 473 }
 474
 475 /* return length of unicode string in bytes */
 476 static int cifs_unicode_bytelen(const char *str)
 477 {
 478         int len;
 479         const __le16 *ustr = (const __le16 *)str;
 480
 481         for (len = 0; len <= PATH_MAX; len++) {
 482                 if (ustr[len] == 0)
 483                         return len << 1;
 484         }
 485         cifs_dbg(FYI, "Unicode string longer than PATH_MAX found\n");
 486         return len << 1;
 487 }
 488
 489 static char *nxt_dir_entry(char *old_entry, char *end_of_smb, int level)
 490 {
 491         char *new_entry;
 492         FILE_DIRECTORY_INFO *pDirInfo = (FILE_DIRECTORY_INFO *)old_entry;
 493
 494         if (level == SMB_FIND_FILE_INFO_STANDARD) {
 495                 FIND_FILE_STANDARD_INFO *pfData;
 496                 pfData = (FIND_FILE_STANDARD_INFO *)pDirInfo;
 497
 498                 new_entry = old_entry + sizeof(FIND_FILE_STANDARD_INFO) +
 499                                 pfData->FileNameLength;
 500         } else {
 501                 u32 next_offset = le32_to_cpu(pDirInfo->NextEntryOffset);
 502
 503                 if (old_entry + next_offset < old_entry) {
 504                         cifs_dbg(VFS, "Invalid offset %u\n", next_offset);
 505                         return NULL;
 506                 }
 507                 new_entry = old_entry + next_offset;
 508         }
 509         cifs_dbg(FYI, "new entry %p old entry %p\n", new_entry, old_entry);
 510         /* validate that new_entry is not past end of SMB */
 511         if (new_entry >= end_of_smb) {
 512                 cifs_dbg(VFS, "search entry %p began after end of SMB %p old entry %p\n",
 513                          new_entry, end_of_smb, old_entry);
 514                 return NULL;
 515         } else if (((level == SMB_FIND_FILE_INFO_STANDARD) &&
 516                     (new_entry + sizeof(FIND_FILE_STANDARD_INFO) > end_of_smb))
 517                   || ((level != SMB_FIND_FILE_INFO_STANDARD) &&
 518                    (new_entry + sizeof(FILE_DIRECTORY_INFO) > end_of_smb)))  {
 519                 cifs_dbg(VFS, "search entry %p extends after end of SMB %p\n",
 520                          new_entry, end_of_smb);
 521                 return NULL;
 522         } else
 523                 return new_entry;
 524
 525 }
 526
 527 struct cifs_dirent {
 528         const char      *name;
 529         size_t          namelen;
 530         u32             resume_key;
 531         u64             ino;
 532 };
 533
 534 static void cifs_fill_dirent_posix(struct cifs_dirent *de,
 535                                    const struct smb2_posix_info *info)
 536 {
 537         struct smb2_posix_info_parsed parsed;
 538
 539         /* payload should have already been checked at this point */
 540         if (posix_info_parse(info, NULL, &parsed) < 0) {
 541                 cifs_dbg(VFS, "Invalid POSIX info payload\n");
 542                 return;
 543         }
 544
 545         de->name = parsed.name;
 546         de->namelen = parsed.name_len;
 547         de->resume_key = info->Ignored;
 548         de->ino = le64_to_cpu(info->Inode);
 549 }
 550
 551 static void cifs_fill_dirent_unix(struct cifs_dirent *de,
 552                 const FILE_UNIX_INFO *info, bool is_unicode)
 553 {
 554         de->name = &info->FileName[0];
 555         if (is_unicode)
 556                 de->namelen = cifs_unicode_bytelen(de->name);
 557         else
 558                 de->namelen = strnlen(de->name, PATH_MAX);
 559         de->resume_key = info->ResumeKey;
 560         de->ino = le64_to_cpu(info->basic.UniqueId);
 561 }
 562
 563 static void cifs_fill_dirent_dir(struct cifs_dirent *de,
 564                 const FILE_DIRECTORY_INFO *info)
 565 {
 566         de->name = &info->FileName[0];
 567         de->namelen = le32_to_cpu(info->FileNameLength);
 568         de->resume_key = info->FileIndex;
 569 }
 570
 571 static void cifs_fill_dirent_full(struct cifs_dirent *de,
 572                 const FILE_FULL_DIRECTORY_INFO *info)
 573 {
 574         de->name = &info->FileName[0];
 575         de->namelen = le32_to_cpu(info->FileNameLength);
 576         de->resume_key = info->FileIndex;
 577 }
 578
 579 static void cifs_fill_dirent_search(struct cifs_dirent *de,
 580                 const SEARCH_ID_FULL_DIR_INFO *info)
 581 {
 582         de->name = &info->FileName[0];
 583         de->namelen = le32_to_cpu(info->FileNameLength);
 584         de->resume_key = info->FileIndex;
 585         de->ino = le64_to_cpu(info->UniqueId);
 586 }
 587
 588 static void cifs_fill_dirent_both(struct cifs_dirent *de,
 589                 const FILE_BOTH_DIRECTORY_INFO *info)
 590 {
 591         de->name = &info->FileName[0];
 592         de->namelen = le32_to_cpu(info->FileNameLength);
 593         de->resume_key = info->FileIndex;
 594 }
 595
 596 static void cifs_fill_dirent_std(struct cifs_dirent *de,
 597                 const FIND_FILE_STANDARD_INFO *info)
 598 {
 599         de->name = &info->FileName[0];
 600         /* one byte length, no endianess conversion */
 601         de->namelen = info->FileNameLength;
 602         de->resume_key = info->ResumeKey;
 603 }
 604
 605 static int cifs_fill_dirent(struct cifs_dirent *de, const void *info,
 606                 u16 level, bool is_unicode)
 607 {
 608         memset(de, 0, sizeof(*de));
 609
 610         switch (level) {
 611         case SMB_FIND_FILE_POSIX_INFO:
 612                 cifs_fill_dirent_posix(de, info);
 613                 break;
 614         case SMB_FIND_FILE_UNIX:
 615                 cifs_fill_dirent_unix(de, info, is_unicode);
 616                 break;
 617         case SMB_FIND_FILE_DIRECTORY_INFO:
 618                 cifs_fill_dirent_dir(de, info);
 619                 break;
 620         case SMB_FIND_FILE_FULL_DIRECTORY_INFO:
 621                 cifs_fill_dirent_full(de, info);
 622                 break;
 623         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
 624                 cifs_fill_dirent_search(de, info);
 625                 break;
 626         case SMB_FIND_FILE_BOTH_DIRECTORY_INFO:
 627                 cifs_fill_dirent_both(de, info);
 628                 break;
 629         case SMB_FIND_FILE_INFO_STANDARD:
 630                 cifs_fill_dirent_std(de, info);
 631                 break;
 632         default:
 633                 cifs_dbg(FYI, "Unknown findfirst level %d\n", level);
 634                 return -EINVAL;
 635         }
 636
 637         return 0;
 638 }
 639
 640 #define UNICODE_DOT cpu_to_le16(0x2e)
 641
 642 /* return 0 if no match and 1 for . (current directory) and 2 for .. (parent) */
 643 static int cifs_entry_is_dot(struct cifs_dirent *de, bool is_unicode)
 644 {
 645         int rc = 0;
 646
 647         if (!de->name)
 648                 return 0;
 649
 650         if (is_unicode) {
 651                 __le16 *ufilename = (__le16 *)de->name;
 652                 if (de->namelen == 2) {
 653                         /* check for . */
 654                         if (ufilename[0] == UNICODE_DOT)
 655                                 rc = 1;
 656                 } else if (de->namelen == 4) {
 657                         /* check for .. */
 658                         if (ufilename[0] == UNICODE_DOT &&
 659                             ufilename[1] == UNICODE_DOT)
 660                                 rc = 2;
 661                 }
 662         } else /* ASCII */ {
 663                 if (de->namelen == 1) {
 664                         if (de->name[0] == '.')
 665                                 rc = 1;
 666                 } else if (de->namelen == 2) {
 667                         if (de->name[0] == '.' && de->name[1] == '.')
 668                                 rc = 2;
 669                 }
 670         }
 671
 672         return rc;
 673 }
 674
 675 /* Check if directory that we are searching has changed so we can decide
 676    whether we can use the cached search results from the previous search */
 677 static int is_dir_changed(struct file *file)
 678 {
 679         struct inode *inode = file_inode(file);
 680         struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
 681
 682         if (cifsInfo->time == 0)
 683                 return 1; /* directory was changed, perhaps due to unlink */
 684         else
 685                 return 0;
 686
 687 }
 688
 689 static int cifs_save_resume_key(const char *current_entry,
 690         struct cifsFileInfo *file_info)
 691 {
 692         struct cifs_dirent de;
 693         int rc;
 694
 695         rc = cifs_fill_dirent(&de, current_entry, file_info->srch_inf.info_level,
 696                               file_info->srch_inf.unicode);
 697         if (!rc) {
 698                 file_info->srch_inf.presume_name = de.name;
 699                 file_info->srch_inf.resume_name_len = de.namelen;
 700                 file_info->srch_inf.resume_key = de.resume_key;
 701         }
 702         return rc;
 703 }
 704
 705 /*
 706  * Find the corresponding entry in the search. Note that the SMB server returns
 707  * search entries for . and .. which complicates logic here if we choose to
 708  * parse for them and we do not assume that they are located in the findfirst
 709  * return buffer. We start counting in the buffer with entry 2 and increment for
 710  * every entry (do not increment for . or .. entry).
 711  */
 712 static int
 713 find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
 714                 struct file *file, const char *full_path,
 715                 char **current_entry, int *num_to_ret)
 716 {
 717         __u16 search_flags;
 718         int rc = 0;
 719         int pos_in_buf = 0;
 720         loff_t first_entry_in_buffer;
 721         loff_t index_to_find = pos;
 722         struct cifsFileInfo *cfile = file->private_data;
 723         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
 724         struct TCP_Server_Info *server = tcon->ses->server;
 725         /* check if index in the buffer */
 726
 727         if (!server->ops->query_dir_first || !server->ops->query_dir_next)
 728                 return -ENOSYS;
 729
 730         if ((cfile == NULL) || (current_entry == NULL) || (num_to_ret == NULL))
 731                 return -ENOENT;
 732
 733         *current_entry = NULL;
 734         first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
 735                                         cfile->srch_inf.entries_in_buffer;
 736
 737         /*
 738          * If first entry in buf is zero then is first buffer
 739          * in search response data which means it is likely . and ..
 740          * will be in this buffer, although some servers do not return
 741          * . and .. for the root of a drive and for those we need
 742          * to start two entries earlier.
 743          */
 744
 745         dump_cifs_file_struct(file, "In fce ");
 746         if (((index_to_find < cfile->srch_inf.index_of_last_entry) &&
 747              is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
 748                 /* close and restart search */
 749                 cifs_dbg(FYI, "search backing up - close and restart search\n");
 750                 spin_lock(&cfile->file_info_lock);
 751                 if (server->ops->dir_needs_close(cfile)) {
 752                         cfile->invalidHandle = true;
 753                         spin_unlock(&cfile->file_info_lock);
 754                         if (server->ops->close_dir)
 755                                 server->ops->close_dir(xid, tcon, &cfile->fid);
 756                 } else
 757                         spin_unlock(&cfile->file_info_lock);
 758                 if (cfile->srch_inf.ntwrk_buf_start) {
 759                         cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
 760                         if (cfile->srch_inf.smallBuf)
 761                                 cifs_small_buf_release(cfile->srch_inf.
 762                                                 ntwrk_buf_start);
 763                         else
 764                                 cifs_buf_release(cfile->srch_inf.
 765                                                 ntwrk_buf_start);
 766                         cfile->srch_inf.ntwrk_buf_start = NULL;
 767                 }
 768                 rc = initiate_cifs_search(xid, file, full_path);
 769                 if (rc) {
 770                         cifs_dbg(FYI, "error %d reinitiating a search on rewind\n",
 771                                  rc);
 772                         return rc;
 773                 }
 774                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 775                 if (cfile->srch_inf.last_entry)
 776                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 777         }
 778
 779         search_flags = CIFS_SEARCH_CLOSE_AT_END | CIFS_SEARCH_RETURN_RESUME;
 780         if (backup_cred(cifs_sb))
 781                 search_flags |= CIFS_SEARCH_BACKUP_SEARCH;
 782
 783         while ((index_to_find >= cfile->srch_inf.index_of_last_entry) &&
 784                (rc == 0) && !cfile->srch_inf.endOfSearch) {
 785                 cifs_dbg(FYI, "calling findnext2\n");
 786                 rc = server->ops->query_dir_next(xid, tcon, &cfile->fid,
 787                                                  search_flags,
 788                                                  &cfile->srch_inf);
 789                 /* FindFirst/Next set last_entry to NULL on malformed reply */
 790                 if (cfile->srch_inf.last_entry)
 791                         cifs_save_resume_key(cfile->srch_inf.last_entry, cfile);
 792                 if (rc)
 793                         return -ENOENT;
 794         }
 795         if (index_to_find < cfile->srch_inf.index_of_last_entry) {
 796                 /* we found the buffer that contains the entry */
 797                 /* scan and find it */
 798                 int i;
 799                 char *cur_ent;
 800                 char *end_of_smb;
 801
 802                 if (cfile->srch_inf.ntwrk_buf_start == NULL) {
 803                         cifs_dbg(VFS, "ntwrk_buf_start is NULL during readdir\n");
 804                         return -EIO;
 805                 }
 806
 807                 end_of_smb = cfile->srch_inf.ntwrk_buf_start +
 808                         server->ops->calc_smb_size(
 809                                         cfile->srch_inf.ntwrk_buf_start);
 810
 811                 cur_ent = cfile->srch_inf.srch_entries_start;
 812                 first_entry_in_buffer = cfile->srch_inf.index_of_last_entry
 813                                         - cfile->srch_inf.entries_in_buffer;
 814                 pos_in_buf = index_to_find - first_entry_in_buffer;
 815                 cifs_dbg(FYI, "found entry - pos_in_buf %d\n", pos_in_buf);
 816
 817                 for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
 818                         /* go entry by entry figuring out which is first */
 819                         cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
 820                                                 cfile->srch_inf.info_level);
 821                 }
 822                 if ((cur_ent == NULL) && (i < pos_in_buf)) {
 823                         /* BB fixme - check if we should flag this error */
 824                         cifs_dbg(VFS, "reached end of buf searching for pos in buf %d index to find %lld rc %d\n",
 825                                  pos_in_buf, index_to_find, rc);
 826                 }
 827                 rc = 0;
 828                 *current_entry = cur_ent;
 829         } else {
 830                 cifs_dbg(FYI, "index not in buffer - could not findnext into it\n");
 831                 return 0;
 832         }
 833
 834         if (pos_in_buf >= cfile->srch_inf.entries_in_buffer) {
 835                 cifs_dbg(FYI, "can not return entries pos_in_buf beyond last\n");
 836                 *num_to_ret = 0;
 837         } else
 838                 *num_to_ret = cfile->srch_inf.entries_in_buffer - pos_in_buf;
 839
 840         return rc;
 841 }
 842
 843 static bool emit_cached_dirents(struct cached_dirents *cde,
 844                                 struct dir_context *ctx)
 845 {
 846         struct cached_dirent *dirent;
 847         int rc;
 848
 849         list_for_each_entry(dirent, &cde->entries, entry) {
 850                 if (ctx->pos >= dirent->pos)
 851                         continue;
 852                 ctx->pos = dirent->pos;
 853                 rc = dir_emit(ctx, dirent->name, dirent->namelen,
 854                               dirent->fattr.cf_uniqueid,
 855                               dirent->fattr.cf_dtype);
 856                 if (!rc)
 857                         return rc;
 858         }
 859         return true;
 860 }
 861
 862 static void update_cached_dirents_count(struct cached_dirents *cde,
 863                                         struct dir_context *ctx)
 864 {
 865         if (cde->ctx != ctx)
 866                 return;
 867         if (cde->is_valid || cde->is_failed)
 868                 return;
 869
 870         cde->pos++;
 871 }
 872
 873 static void finished_cached_dirents_count(struct cached_dirents *cde,
 874                                         struct dir_context *ctx)
 875 {
 876         if (cde->ctx != ctx)
 877                 return;
 878         if (cde->is_valid || cde->is_failed)
 879                 return;
 880         if (ctx->pos != cde->pos)
 881                 return;
 882
 883         cde->is_valid = 1;
 884 }
 885
 886 static void add_cached_dirent(struct cached_dirents *cde,
 887                               struct dir_context *ctx,
 888                               const char *name, int namelen,
 889                               struct cifs_fattr *fattr)
 890 {
 891         struct cached_dirent *de;
 892
 893         if (cde->ctx != ctx)
 894                 return;
 895         if (cde->is_valid || cde->is_failed)
 896                 return;
 897         if (ctx->pos != cde->pos) {
 898                 cde->is_failed = 1;
 899                 return;
 900         }
 901         de = kzalloc(sizeof(*de), GFP_ATOMIC);
 902         if (de == NULL) {
 903                 cde->is_failed = 1;
 904                 return;
 905         }
 906         de->namelen = namelen;
 907         de->name = kstrndup(name, namelen, GFP_ATOMIC);
 908         if (de->name == NULL) {
 909                 kfree(de);
 910                 cde->is_failed = 1;
 911                 return;
 912         }
 913         de->pos = ctx->pos;
 914
 915         memcpy(&de->fattr, fattr, sizeof(struct cifs_fattr));
 916
 917         list_add_tail(&de->entry, &cde->entries);
 918 }
 919
 920 static bool cifs_dir_emit(struct dir_context *ctx,
 921                           const char *name, int namelen,
 922                           struct cifs_fattr *fattr,
 923                           struct cached_fid *cfid)
 924 {
 925         bool rc;
 926         ino_t ino = cifs_uniqueid_to_ino_t(fattr->cf_uniqueid);
 927
 928         rc = dir_emit(ctx, name, namelen, ino, fattr->cf_dtype);
 929         if (!rc)
 930                 return rc;
 931
 932         if (cfid) {
 933                 mutex_lock(&cfid->dirents.de_mutex);
 934                 add_cached_dirent(&cfid->dirents, ctx, name, namelen,
 935                                   fattr);
 936                 mutex_unlock(&cfid->dirents.de_mutex);
 937         }
 938
 939         return rc;
 940 }
 941
 942 static int cifs_filldir(char *find_entry, struct file *file,
 943                         struct dir_context *ctx,
 944                         char *scratch_buf, unsigned int max_len,
 945                         struct cached_fid *cfid)
 946 {
 947         struct cifsFileInfo *file_info = file->private_data;
 948         struct super_block *sb = file_inode(file)->i_sb;
 949         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 950         struct cifs_dirent de = { NULL, };
 951         struct cifs_fattr fattr;
 952         struct qstr name;
 953         int rc = 0;
 954
 955         rc = cifs_fill_dirent(&de, find_entry, file_info->srch_inf.info_level,
 956                               file_info->srch_inf.unicode);
 957         if (rc)
 958                 return rc;
 959
 960         if (de.namelen > max_len) {
 961                 cifs_dbg(VFS, "bad search response length %zd past smb end\n",
 962                          de.namelen);
 963                 return -EINVAL;
 964         }
 965
 966         /* skip . and .. since we added them first */
 967         if (cifs_entry_is_dot(&de, file_info->srch_inf.unicode))
 968                 return 0;
 969
 970         if (file_info->srch_inf.unicode) {
 971                 struct nls_table *nlt = cifs_sb->local_nls;
 972                 int map_type;
 973
 974                 map_type = cifs_remap(cifs_sb);
 975                 name.name = scratch_buf;
 976                 name.len =
 977                         cifs_from_utf16((char *)name.name, (__le16 *)de.name,
 978                                         UNICODE_NAME_MAX,
 979                                         min_t(size_t, de.namelen,
 980                                               (size_t)max_len), nlt, map_type);
 981                 name.len -= nls_nullsize(nlt);
 982         } else {
 983                 name.name = de.name;
 984                 name.len = de.namelen;
 985         }
 986
 987         switch (file_info->srch_inf.info_level) {
 988         case SMB_FIND_FILE_POSIX_INFO:
 989                 cifs_posix_to_fattr(&fattr,
 990                                     (struct smb2_posix_info *)find_entry,
 991                                     cifs_sb);
 992                 break;
 993         case SMB_FIND_FILE_UNIX:
 994                 cifs_unix_basic_to_fattr(&fattr,
 995                                          &((FILE_UNIX_INFO *)find_entry)->basic,
 996                                          cifs_sb);
 997                 break;
 998         case SMB_FIND_FILE_INFO_STANDARD:
 999                 cifs_std_info_to_fattr(&fattr,
1000                                        (FIND_FILE_STANDARD_INFO *)find_entry,
1001                                        cifs_sb);
1002                 break;
1003         case SMB_FIND_FILE_ID_FULL_DIR_INFO:
1004                 cifs_fulldir_info_to_fattr(&fattr,
1005                                            (SEARCH_ID_FULL_DIR_INFO *)find_entry,
1006                                            cifs_sb);
1007                 break;
1008         default:
1009                 cifs_dir_info_to_fattr(&fattr,
1010                                        (FILE_DIRECTORY_INFO *)find_entry,
1011                                        cifs_sb);
1012                 break;
1013         }
1014
1015         if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
1016                 fattr.cf_uniqueid = de.ino;
1017         } else {
1018                 fattr.cf_uniqueid = iunique(sb, ROOT_I);
1019                 cifs_autodisable_serverino(cifs_sb);
1020         }
1021
1022         if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
1023             couldbe_mf_symlink(&fattr))
1024                 /*
1025                  * trying to get the type and mode can be slow,
1026                  * so just call those regular files for now, and mark
1027                  * for reval
1028                  */
1029                 fattr.cf_flags |= CIFS_FATTR_NEED_REVAL;
1030
1031         cifs_prime_dcache(file_dentry(file), &name, &fattr);
1032
1033         return !cifs_dir_emit(ctx, name.name, name.len,
1034                               &fattr, cfid);
1035 }
1036
1037
1038 int cifs_readdir(struct file *file, struct dir_context *ctx)
1039 {
1040         int rc = 0;
1041         unsigned int xid;
1042         int i;
1043         struct tcon_link *tlink = NULL;
1044         struct cifs_tcon *tcon;
1045         struct cifsFileInfo *cifsFile;
1046         char *current_entry;
1047         int num_to_fill = 0;
1048         char *tmp_buf = NULL;
1049         char *end_of_smb;
1050         unsigned int max_len;
1051         const char *full_path;
1052         void *page = alloc_dentry_path();
1053         struct cached_fid *cfid = NULL;
1054         struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
1055
1056         xid = get_xid();
1057
1058         full_path = build_path_from_dentry(file_dentry(file), page);
1059         if (IS_ERR(full_path)) {
1060                 rc = PTR_ERR(full_path);
1061                 goto rddir2_exit;
1062         }
1063
1064         if (file->private_data == NULL) {
1065                 tlink = cifs_sb_tlink(cifs_sb);
1066                 if (IS_ERR(tlink))
1067                         goto cache_not_found;
1068                 tcon = tlink_tcon(tlink);
1069         } else {
1070                 cifsFile = file->private_data;
1071                 tcon = tlink_tcon(cifsFile->tlink);
1072         }
1073
1074         rc = open_cached_dir(xid, tcon, full_path, cifs_sb, false, &cfid);
1075         cifs_put_tlink(tlink);
1076         if (rc)
1077                 goto cache_not_found;
1078
1079         mutex_lock(&cfid->dirents.de_mutex);
1080         /*
1081          * If this was reading from the start of the directory
1082          * we need to initialize scanning and storing the
1083          * directory content.
1084          */
1085         if (ctx->pos == 0 && cfid->dirents.ctx == NULL) {
1086                 cfid->dirents.ctx = ctx;
1087                 cfid->dirents.pos = 2;
1088         }
1089         /*
1090          * If we already have the entire directory cached then
1091          * we can just serve the cache.
1092          */
1093         if (cfid->dirents.is_valid) {
1094                 if (!dir_emit_dots(file, ctx)) {
1095                         mutex_unlock(&cfid->dirents.de_mutex);
1096                         goto rddir2_exit;
1097                 }
1098                 emit_cached_dirents(&cfid->dirents, ctx);
1099                 mutex_unlock(&cfid->dirents.de_mutex);
1100                 goto rddir2_exit;
1101         }
1102         mutex_unlock(&cfid->dirents.de_mutex);
1103
1104         /* Drop the cache while calling initiate_cifs_search and
1105          * find_cifs_entry in case there will be reconnects during
1106          * query_directory.
1107          */
1108         close_cached_dir(cfid);
1109         cfid = NULL;
1110
1111  cache_not_found:
1112         /*
1113          * Ensure FindFirst doesn't fail before doing filldir() for '.' and
1114          * '..'. Otherwise we won't be able to notify VFS in case of failure.
1115          */
1116         if (file->private_data == NULL) {
1117                 rc = initiate_cifs_search(xid, file, full_path);
1118                 cifs_dbg(FYI, "initiate cifs search rc %d\n", rc);
1119                 if (rc)
1120                         goto rddir2_exit;
1121         }
1122
1123         if (!dir_emit_dots(file, ctx))
1124                 goto rddir2_exit;
1125
1126         /* 1) If search is active,
1127                 is in current search buffer?
1128                 if it before then restart search
1129                 if after then keep searching till find it */
1130         cifsFile = file->private_data;
1131         if (cifsFile->srch_inf.endOfSearch) {
1132                 if (cifsFile->srch_inf.emptyDir) {
1133                         cifs_dbg(FYI, "End of search, empty dir\n");
1134                         rc = 0;
1135                         goto rddir2_exit;
1136                 }
1137         } /* else {
1138                 cifsFile->invalidHandle = true;
1139                 tcon->ses->server->close(xid, tcon, &cifsFile->fid);
1140         } */
1141
1142         tcon = tlink_tcon(cifsFile->tlink);
1143         rc = find_cifs_entry(xid, tcon, ctx->pos, file, full_path,
1144                              &current_entry, &num_to_fill);
1145         open_cached_dir(xid, tcon, full_path, cifs_sb, false, &cfid);
1146         if (rc) {
1147                 cifs_dbg(FYI, "fce error %d\n", rc);
1148                 goto rddir2_exit;
1149         } else if (current_entry != NULL) {
1150                 cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
1151         } else {
1152                 if (cfid) {
1153                         mutex_lock(&cfid->dirents.de_mutex);
1154                         finished_cached_dirents_count(&cfid->dirents, ctx);
1155                         mutex_unlock(&cfid->dirents.de_mutex);
1156                 }
1157                 cifs_dbg(FYI, "Could not find entry\n");
1158                 goto rddir2_exit;
1159         }
1160         cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
1161                  num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
1162         max_len = tcon->ses->server->ops->calc_smb_size(
1163                         cifsFile->srch_inf.ntwrk_buf_start);
1164         end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
1165
1166         tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
1167         if (tmp_buf == NULL) {
1168                 rc = -ENOMEM;
1169                 goto rddir2_exit;
1170         }
1171
1172         for (i = 0; i < num_to_fill; i++) {
1173                 if (current_entry == NULL) {
1174                         /* evaluate whether this case is an error */
1175                         cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
1176                                  num_to_fill, i);
1177                         break;
1178                 }
1179                 /*
1180                  * if buggy server returns . and .. late do we want to
1181                  * check for that here?
1182                  */
1183                 *tmp_buf = 0;
1184                 rc = cifs_filldir(current_entry, file, ctx,
1185                                   tmp_buf, max_len, cfid);
1186                 if (rc) {
1187                         if (rc > 0)
1188                                 rc = 0;
1189                         break;
1190                 }
1191
1192                 ctx->pos++;
1193                 if (cfid) {
1194                         mutex_lock(&cfid->dirents.de_mutex);
1195                         update_cached_dirents_count(&cfid->dirents, ctx);
1196                         mutex_unlock(&cfid->dirents.de_mutex);
1197                 }
1198
1199                 if (ctx->pos ==
1200                         cifsFile->srch_inf.index_of_last_entry) {
1201                         cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
1202                                  ctx->pos, tmp_buf);
1203                         cifs_save_resume_key(current_entry, cifsFile);
1204                         break;
1205                 } else
1206                         current_entry =
1207                                 nxt_dir_entry(current_entry, end_of_smb,
1208                                         cifsFile->srch_inf.info_level);
1209         }
1210         kfree(tmp_buf);
1211
1212 rddir2_exit:
1213         if (cfid)
1214                 close_cached_dir(cfid);
1215         free_dentry_path(page);
1216         free_xid(xid);
1217         return rc;
1218 }